Missouri trailer laws and regulations
Missouri trailer rules from the DOR: 3,000 lb title and brake thresholds, dimension caps, mandatory safety chains and which roads allow what width.
In Missouri, 3,000 lb is the line that matters. Trailers above that need to be titled, registered and equipped with their own brake system. Below it, registration and brakes aren’t mandatory, but liability insurance is still a smart idea because your auto policy won’t cover trailer damage.
Dimension limits vary by road. The general state width cap is 96 inches, but interstates and designated highways allow 102 inches. Height is 13.5 ft on most roads and 14 ft on designated routes.
Quick reference
| Item | Missouri rule |
|---|---|
| Title and registration | Trailers over 3,000 lb GVW |
| Brakes required | Trailers over 3,000 lb GVW |
| Max trailer length | 45 ft including load |
| Max combo length | 60 ft (semi-truck combos) |
| Max width (general) | 96 in |
| Max width (interstate/designated) | 102 in |
| Max height (general) | 13 ft 6 in |
| Max height (designated) | 14 ft |
| Safety chain | Required unless using 5th-wheel or gooseneck |
Registration and titles
Trailers over 3,000 lb gross weight have to be titled and registered through the Missouri Department of Revenue. Under 3,000 lb, registration is optional, but plenty of owners do it anyway for proof of ownership and to make insurance claims simpler.
Trailer insurance isn’t required by state law. The catch is that your auto insurance won’t cover damage to or caused by the trailer, so liability coverage on the trailer is worth thinking about even when the law doesn’t force it.
General towing rules
Missouri doesn’t have a long list of unusual towing rules. If something is illegal in normal driving, it’s illegal with a trailer attached.
Dimensions by road class
The trailer body maxes out at 45 ft including the load. Tow vehicle plus trailer can run up to 60 ft on semi-tractor-trailer combinations.
Width depends on the road. Most state roads cap at 96 inches. Interstates and other designated highways allow up to 102 inches. Height is 13 ft 6 in on most roads, 14 ft on designated routes. If you’re running near the limit, plan the route before you load.
Hitches and chains
In addition to the primary coupling, safety chains (or similar device) are mandatory unless you’re on a 5th-wheel or gooseneck connection.
Lighting rules
The trailer needs two red tail lamps on the rear, two reflectors, and a white licence plate light. If hand or arm signals from the driver aren’t visible (which is most of the time with a trailer in the way), the trailer also needs turn signals and brake lights.
Speed limits while towing
Missouri doesn’t post a different towing speed. The posted limit applies. Sway or loss of control at the limit can still get you cited for an unsafe combination.
Mirror rules
If the trailer or load blocks the rear view through the cab, the tow vehicle needs a mirror adjusted so the driver can see the road behind from the driver’s seat. That’s the wording in the statute. In practice it means outside mirrors on both sides, often with slip-on extenders for wider loads.
Brake rules
A trailer with a GVWR over 3,000 lb has to have its own braking system. Trailers using a fifth-wheel coupling and trailers hauling hazardous materials at or above 3,000 lb need a separate brake system regardless of how they’re hitched.
A note on Ford trailer wiring in 2026
If you tow with a 2021 to 2026 Ford F-150, 2022 to 2026 Super Duty, 2022 to 2026 Maverick or Expedition, or a 2024 to 2026 Ranger, recall 26C10 (NHTSA 26V104000) covers an Integrated Trailer Module software fault that can affect trailer lights and brake control. Ford pushed the OTA fix in March 2026, but if the truck wasn’t OTA-enrolled, a dealer reflash may still be pending.